Field of Invention
This invention relates to steering and manipulating electromagnetic beams, and particularly to steering and manipulating beams utilizing interferometric schemes.
Description of Prior Art
Electromagnetic beam steering has applications in free space optical communication, remote sensing, and compact projectors. Compared to conventional mechanical beam steering, nonmechanical beam steering has advantages of fast speed, compact structure, and potentially low cost. Current nonmechanical schemes include steering a collimated beam using phased array [P. F. McManamon, et al, “A Review of Phased Array Steering for Narrow-Band Electrooptical Systems”, Proceedings of the IEEE, 97, 6, 1078 (2009)], and steering or shaping a divergent beam using plasmonics and phase manipulation [F. Capasso, et al, “Methods and Apparatus for Improving Collimation of Radiation Beams”, US Patent Application #20100226134, (2010), and D. C. Adams, et al, “Plasmonic mid-IR beam steering”, Applied Physics Letter, 96, 201112, (2010)]. However, both nonmechanical methods involve a large number of beams having equal or moderate intensity, which usually means a complex structure and unnecessary power loss.
Therefore, there exists a need for beam steering scheme which requires less quantity of beams and lower beam intensity for the majority of beams involved in the process.
Beam as a term used here means any electromagnetic beam or electromagnetic wave which follows the Maxwell equations. Consequently, a beam may be of radiation in optical frequency range or radio frequency range, or in between, or beyond the two ranges.